I have experienced all these instabilities and more. Once I disabled output through my old Black Magic card to my SDI monitor they about 90% went away. Of course now I can’t monitor except on my other Cinema display, but I’ve just ordered a new BM Monitor Mini which I’m told by BM should work fine with CS6.
BUT yesterday I downloaded Premiere Pro CC and it will not play any media files. Period. Hit the play button in the source or program monitors and the triangle turns into a square, and that’s it. No joy.
I REALLY love how Premiere CC has upgraded many features that basically give it more of the functionality of FCP7, I’m sure what I’m experiencing here has a solution, and I’m eager to find it. Eager!